CHEMOTAXIS OF LEUCOCYTES 257 



Negative Chemotaxis. — Probably the substances that repel leuco- 

 cytes are iV-w in number; Kantliack, indeed, doubted the existence of 

 really negative cliemotactic action upon leucocytes. Verigo ^° also 

 considoi's that as yet no actual negative chemotaxis has been satisfac- 

 torily demonstrated; but, by analogy with the effects of chemicals on 

 amebae, ciliata, and plasmodial forms, which all siiow a decided nega- 

 tive chemotaxis under certain influences, it would seem most probable 

 that leucocytes also should be repelled as well as attracted by chem- 

 icals.^^ 



Non=bacterial Chemotactic Substances. — One of the earliest sig- 

 nificant studies of the effects of non-bacterial substances upon chem- 

 otaxis was made by ]\Iassart and Bordet,^- who showed that products 

 of the disintegration of leucocytes and other cells had a strong posi- 

 tive chemotactic influence. They also corroborated the statement of 

 Yaillard and Vincent that lactic acid is an actively- repellant sub- 

 stance, for they found that tubes containing a pyocyaneus culture, 

 which ordinarily became filled with leucocytes rapidly, did not become 

 invaded at all if lactic acid was also added in a strength of 1 : 500, 

 although leucocytes did enter when the dilution was 1 : 1000. 



Gabritchevsky ^^ studied the chemical influence of a large number 

 of substances on leucocytes and divided them into three groups : I. 

 Substances exerting "negative chemotaxis," including those that at- 

 tracted only a few leucocytes.^* II. Substances with "indifferent 

 chemotaxis," which attracted moderate numbers of leucocytes. III. 

 Substances with positive chemotaxis. If we correct the groupings 

 made by Gabritchevsky we have the following classification: 



I. Substances negatively chemotactic or indifferent : 



(a) Concentrated solutions of sodium and potassium salts; 

 (&) Lactic acid in all concentrations; (c) quinine (0.5 per 

 cent.) ; (d) alcohol (10 per cent.) ; (e) chloroform in wa- 

 tery solution; (/) jequirity (2 per cent., passed through 

 Chamberland filter) ; (g) glycerol (10 per cent, to 1 per 

 cent.); (h) bile; (i) B. cliolerae gaUinarium. 

 II. Substances with feeble chemotaxis : 



(a) Distilled water; (&) dilute solutions of sodium and 



10 Arch. d. MM. exper., 1001 (13), .585. 



11 Salomonsen's observation (Festskrift ved indvielsen af Statens Sorum In- 

 stitut, Kopenhagen. 1902, Art. XII), that ciliated infusoria when killed show 

 a strong negative effect on other ciliates, is of much interest, particularly as it 

 seems to be the opposite of tlie positively chemotactic effect of dead upon living 

 leucocytes. The negative reaction of different ciliata was specific for their own 

 kind rjuantitatively. but not qualitativelv. 



12 Ann. d. I'Inst! Pasteur, 1891 (5), 417. 



13 Ann. d. Tlnst. Pasteur, 1890 (4), 346. 



1* Evidently these substances were not all negatively chemotactic, but were 

 relatively sliQ;htly chemotactic or indifferent: yet in the literature generally these 

 experiments Jiave been cited as indicating a negative chemotactic influence of the 

 substances .studied. 

 17 



